The known means for lifting and carrying containers are divided roughly in two kinds, at least as for the possibility of rotating the container during transportation around a vertical axis.
The first kind comprises that a container is lifted from a store and, remaining parallel to itself, is carried to another place, for instance from the pier to the ship, from a point of the pier to another, or from a point of the ship to another.
The second type comprises on the contrary that a container may rotate about a vertical axis, for instance for better utilizing the available space on a pier or a ship.
Most of the known devices for handling containers are of the first kind, as those of the second kind, allowing the container to rotate, are much more complicated and expensive than the first ones.
In fact, the known devices of the second kind comprise a carriage sliding on the main bar of the container handling crane and a turnable platform resting on said carriage or hanging below thereof. Said platform on its turn supports, through a suitable system of cables known per se, a crossbar catching the container, called a spreader.
As said platform is turnable about a vertical axis, also the container and relevant spreader will be turnable about said vertical axis.
Said platform is provided with winding drums for the cables supporting said spreader, and said drums need for their movement engines arranged on said platform.
Therefore, the known devices for rotating containers are to be provided with a rotating platform of the kind above-mentioned, said platform being very heavy with respect to the container and spreader with the consequence that said devices are much more expensive than those not allowing said rotation.
Besides, the presence of said rotating platform on which are arranged the winding drums for the cables supporting the container, and the relevant actuating engines, makes completely different the two kinds of devices, in fact the first kind cannot be transformed into a device of the second kind.